Some active pharmaceutical ingredients which cause gelling under a certain condition have been known (Patent Literatures 1 to 7 and Non-Patent Literatures 1 and 2). In general, when a solid formulation is orally administrated, the solid formulation readily disintegrates in the gastrointestinal tract to dissolve an active pharmaceutical ingredient, so that the active pharmaceutical ingredient is absorbed into the body. However, when a solid formulation which contains an active pharmaceutical ingredient causing gelling is administrated, there is a problem in which the active pharmaceutical ingredient is gelled to delay the disintegration of the solid formulation, and delay the dissolution of the active pharmaceutical ingredient.
As conventional techniques of improving delay in disintegration due to gelling, a method of adding cyclodextrin to suppress gel formation or secure the water permeability of a gel layer (Non-Patent Literatures 1 and 2), a method of adding a disintegrant (Non-Patent Literature 1), a method of adding silicates (Patent Literatures 1 to 3), a method of making a drug finer and causing a carrier to adsorb the drug (Patent Literature 4), a method of rapidly breaking a film coating to disintegrate a drug-containing core before gelling (Patent Literature 5), a method using an acidic or basic additive (Patent Literature 6), and a method of achieving a molecular dispersion form in which a drug is dispersed in a polymer (Patent Literature 7) have been known.
As a formulation containing a quinolone carboxylic acid antimicrobial agent in which a main drug is stabilized, an oral composition which contains an acidic additive (Patent Literature 8) and an injection formulation which contains an acidic additive (Patent Literatures 9 and 10) have been known.